We then set up a Huawei Nova 3 (Review) and noted that the numbers weren't present, but they popped up a moment later. This unit also had no SIM card and we didn't allow the phone to connect to Wi-Fi during the setup process. Interestingly, we then repeated the factory reset process on both phones and found that while the two numbers did not pop up in the P20 Pro's phonebook the second time, they did the third time. They were also ready and waiting for us on the Nova 3.

The third unit we checked was a OnePlus 6 (Review), which had been lying idle with a Wi-Fi connection and had not freshly reformatted. Both numbers were present in the address book. Post a reformat, they were still there. The same was true when we went through the setup process on a OnePlus 5T (Review) that had previously been factory reset.

In all cases, we went through the setup process with Wi-Fi disabled and no SIM cards inserted. We left all settings at their defaults and skipped all optional steps. We did not sign in with a Google account or provide any form of personal identification.

We've reached out to OnePlus, Huawei, Xiaomi, and other OEMs for comments and will update this story as and when we hear back from them.

Jamshed AvariEmail Jamshed
Jamshed Avari has been working in tech journalism as a writer, editor and reviewer for over eight years. He has reviewed hundreds of products ranging from smartphones and ... More